Breech block with quadruple thread



Nov. 22, 1960 M. A. REX 2,960,916

BREECH BLOCK WITH QUADRUPLE THREAD Filed May 11, 1959 A-Rex IN VEN TOR.

United States Patent 2,9683% Patented Nov. 22, 1960 BREECH BLOCK WITHQUADRUPLE THREAD Martin A. Rex, Wilmette, IlL, assignor to the UnitedStates of America as represented by the Secretary of the Army Filed May11, 1959, Ser. No. 812,567

1 Claim. (Cl. 89-20) This invention relates to breech loading ordnanceand particularly to new and useful improvements in the breech mechanismof guns of the quick-fire, breech load type.

In the past the conventional interrupted thread type of breech blockshas been equipped with many rows of threads.

It is an object of this invention to provide a gun with a breech blockhaving few threads and consequently a block of reduced axial thickness.Since on the breech block periphery only four single tooth sections of aquadruple thread are required, this desired reduction in axial thicknessis accomplished.

It is a further object of this invention to provide a gun which may berapidly loaded and reloaded. This is achieved because after loading onlya quarter turn of the breech block is needed to tightly seal the breechend of the gun barrel.

In accordance with these and other objects which will become apparenthereinafter, the instant invention will now be described with referenceto the accompanying drawings which illustrate an embodiment thereof.

Figure 1 is a sectional side elevation of the instant invention; and

Figures 2, 3, and 4 are sectional views illustrating optional methods ofsealing the block to the barrel.

Referring now to Figure 1, there is shown the breech loading end of agun barrel. The barrel 1 has therein an axial bore 2, which isinternally threaded at the breech end thereof as at 3. The barrel bore 2has a chamfered shoulder seat 4 for seating a breech block body 5. Thecylindrically shaped breech block body 5 is adapted for engagement withthe internal barrel threads 3. On the periphery of the breech block body5, there is provided a series of quarter turn stub tooth Acme threads 9,10, 11, and 12, for engagement with the aforesaid barrel threads. Thefour individual tooth sections on the breech block body 5 extendperipherally through consecutive arcs of approximately 90, and the toothsections are equally spaced around this periphery. The breech block body5 has on the forward end thereof a chamfered shoulder 8 for engagementwith the aforementioned seat 4. Extending into the barrel bore 2, thereis a forwardly extending projection of lesser diame ter 6. Thisprojection 6 has a beveled pilot section 7 which guides the block 5 intobarrel bore 2. The diameter at the rear of the breech block body 5decreases uniformly along an oblique line 13 to a predetermined point 14at which the diameter is reduced along a radial line 15 to a point ofintersection 16 with the breech body shank 17. The shank 17 has a shankextension 18 integral therewith which has a reduced radius and isthreaded at the end thereof as at 19. A carrier 20 is pivotably attachedto a pintle on the barrel as at 23. The carrier is provided with a bore21 and a counter bore 22 which are respectively of substantially thesame diameter. as the breech block shank extension 18 and the shank 17and which are for the purpose of receiving the shank 17. The shankextension 18 protrudes through the carrier bore 21 and a cap 24 isfastened onto the shank end 19 and thus the shank 17, block 5, andcarrier 20 are held together so that they pivot as a unit about thepintle 23. The carrier 20 is provided with a flange as at 25 which abutsthe barrel 18 and in the loading operation this acts as an aid in theprepositioning of the block 5 relative to the barrel 1 by virtue of thefact that it stops the forward movement of the breech block relative tothe barrel. The cap 24 has integral therewith a handle 26 for turningthe breech block 5 into the barrel 1.

In operation the barrel 1 is loaded from the opened breech end and thenthe carrier 20 is pivoted on the pintle 23 thereby prepositioning thebreech block body 5 relative to the barrel 1 because their respectivelongitudinal axis are then lying along the same line. The handle 26 isthen turned one quarter turn which draws the breech block 5 tightly intothe barrel bore 2 seating the block on the shoulder therein provided.

The barrel bore 2 may have therein an annular groove 27 as in Figures 2,3 and 4, for the purpose of receiving a sealing ring and therebyinsuring a fluid tight, leak proof fit.

Referring specifically to Figure 2, the breech block 5 is provided witha cylindrical projection of reduced diameter 29, said projection havinga pilot section 30 of slightly reduced diameter for guiding theprojection into the barrel 31. The barrel 31 has an annular groovetherein as at 27, which is located in the bore 2, shown. This groove 27,is adapted to receive a sealing ring 28 of the type having a rectangularcross section. When the teaching herein is utilized the figureillustrates how effective sealing is accomplished without the use of thechamfered shoulder 4 as shown in Figure 1.

Figure 3 further illustrates the use of an 0 type sealing ring 32 havinga circular cross sectional area, this ring 32 being adapted to fit anannular groove 27 Thus this arrangement functions in accordance with theremarks made in reference to Figure 2.

In general Figure 4 discloses an arrangement which combines thechamfered shoulder method as revealed in Figure 1 and the sealing ringmethod as illustrated in Figures 2 and 3. A charnfered shoulder 33 restson the charnfered seat 34, and the breech block projection 35 has influid tight relation therewith a sealing ring 36" which encompasses theprojection and which fits into an annular groove 27".

While the instant invention has been shown and described herein in amost practical embodiment, it is recognized that departures may be madetherefrom within the scope of the invention, which is therefore not tobe limited to the details disclosed herein but is to be awarded the fullscope of the claim so as to embrace any and all equivalent apparatus andarticles.

What is claimed is:

A gun comprising, in combination, a cylindrical breech i it 2,960,916

block, said shank being axially received in said carrier,

a handle fixed on the rearward end of said shank, and sealing meanscarried by the forward end of said breech block, said sealing meanssealing between said breech block and said gun barrel when said breechblock is 5 screwed into a locked position in said gun barrel.

References Cited in the file of this patent UNITED STATES PATENTS1,076,842 Schneider Oct. 28, 1913 2,115,743 Niblett May 3, 19382,483,421 Kroeger et a1 Oct. 4, 1949

